The Green Book
Standards for Internal Control in the Federal Government, known as the "Green Book," sets the standards for an effective internal control system for federal agencies.
Standards for Internal Control in the Federal Government—known as the Green Book—sets the standards for an effective internal control system for federal agencies. The 2025 Green Book was effective beginning with fiscal year 2026.
TheGreen Book sets the standards for an effective internal control system for federal agencies.
What is internal control?
Internal control is a process used by management to help an agency achieve its objectives.
How does internal control work?
Internal control helps an agency:
Run its operations efficiently and effectively
Report reliable information about its operations
Comply with applicable laws and regulations
Who would use the Green Book?
Federal executive branch agencies are required to establish internal controls in accordance with the standards in the Green Book. Users of the Green Book may include, but are not limited to:
Program and financial managers at a federal agency
Inspector general staff conducting a financial or performance audit
Independent public accountants conducting an audit of expenditures of federal dollars to state agencies
Compliance officers responsible for making sure that personnel have completed required training
How does an agency use the Green Book?
An agency uses the Green Book to design, implement, and operate internal controls to achieve its objectives related to operations, reporting, and compliance.
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How is the Green Book organized?
The standards in the Green Book are organized by the five components of internal control shown below. Each of the five components contains multiple principles. Principles are the requirements of each component. Each principle has application guidance, called attributes, that provides further explanation of the principle and may also contain minimum documentation requirements.
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Legislative authority
Federal Managers’ Financial Integrity Act (FMFIA) requires the Comptroller General to issue standards for internal control in the federal government. FMFIA requires federal executive branch agencies to establish internal control in accordance with these standards, and to periodically review and annually report on their internal control systems.
Use by other agencies
The Green Book may also be adopted by federal agencies outside the executive branch and by nonfederal groups (such as state, local, and quasi-governmental agencies and nonprofit organizations) as a framework for an internal control system.
Resources
Green Book Appendixes
The 2025 Green Book includes two appendixes which provide additional information related to control activities, examples of sources of data, and references to additional resources that management may leverage in designing, implementing, and operating effective internal control systems to address risks, including areas related to fraud, improper payments, and information security.
Appendix II: Examples of Preventive and Detective Control Activities and Sources of Data
Appendix III: Additional Resources
Related Guidance
Managers and auditors may use the Green Book in conjunction with professional guidance issued by GAO and other organizations, such as:
Committee of Sponsoring Organizations of the Treadway Commission, Internal Control - Integrated Framework, May 2013
Printed Copies
Copies of the 2025 Green Book are available for purchase through the U.S. Government Accountability Office at OrderingCopies@gao.gov. See Order Copies for more information.
Prior Green Book Revisions
Standards for Internal Control in the Federal Government: 2014 Revision (Supersedes AIMD-00-21.3.1) GAO-14-704G Publicly Released: Sep 10, 2014
Standards for Internal Control in the Federal Government: 1999 Revision (Supersedes the 1983 issuance) AIMD-00-21.3.1 Publicly Released: Nov 01, 1999
Before GAO begins updates to the Green Book, the Comptroller General of the United States appoints an advisory council to review the standards and provide recommendations for revisions. The council includes individuals knowledgeable in internal control drawn from:
federal, state, and local government;
the private sector; and
academia.
Advisory council members serve 2-year terms and may be reappointed by the Comptroller General.
GAO Contacts
For technical or practice questions regarding the Green Book please call (202) 512-9535 or e-mail GreenBook@gao.gov.
To receive updates and information related to standards, send an email with the subject “Subscribe” to TheStandardsTeam@gao.gov.
